P4 and on Memory Mapping

["Ross Myers" <ponty@axis.jeack.com.au>]

Hi all,

On and off I've been working through a 16176424 Memcal, I've got some
questions on the A/D Converter in GM's 68pin HC11 type CPU, this CPU is
numbered 16127475.
Here's what I've found -

The Motorola HC11F1 book states that the A/D registers are at -
$1030 (ADCTL)
$1031 (ADR1)
$1032 (ADR2)
$1033 (ADR3)
$1034 (ADR4)
$1039 (OPTION)

>From my disassembly of a '424' Memcal these match O.K but they are mapped
from $30xx, so the ADR's are at $3031 - $3034.
Is this a Remap of the system or is that where GM requests these to be put
in their CPU's?.

That being the case how comparable are the rest of the registers?, Port
locations?.

NEXT PROBLEM -

When an A/D conversion is requested in this PCM it does 4 channels at a
time, but before it does it jumps to the following two routines, I think
they are setting up which channels to read (0-3) or (4-7). Please assembly
guru's help me out here.
Hope it all lines up -
-----------------------------------------

ldx #0x3000    ;A/D or CPU location?
sei            ;Disable Interupts

ldaa #0x07     ;??
jsr Routine1   ;?? Shown Below

ldaa #0x10     ;??
jsr Routine2   ;?? Shown Below

ldaa 0x31,x    ;A/D ADR1 - $3031
staa IATA2D    ;Store A/D IAT Value
ldaa 0x32,x    ;A/D ADR2 - $3032
staa CTSA2D    ;Store A/D CTS Value
ldaa 0x33,x    ;A/D ADR3 - $3033
staa TTSA2D    ;Store A/D TTS Value
ldaa 0x34,x    ;A/D ADR4 - $3034
staa BATA2D    ;Store A/D Batt Voltage

cli            ;Re-enable interrupts

**************************************
Routine1:
bclr 0x08,x,#0x38
lsla
lsla
lsla
oraa 0x08,x
staa 0x08,x
rts

**************************************
Routine2:
    staa ADCTL        ;Store at A/D Control
    ldab #0x0C
LAB1: brset 0x30,x,#0x80,LAB2
    decb
    bne LAB1
LAB2: rts

***************************************


And lastly, we refer to the 68HC11 based ECM/PCM's as P4's right, however
what I don't get is the 808/165 etc use a 52pin CPU, whereas alot of the
later ECM/PCM's use a 68pin, different CPU's right, why the same Px
designation then?

I've been out working in the garden all day, had too much time to think
about all this stuff :-)

Thanks,
Ross Myers